[FEATURE] Adding an alt text field to uploaded images

**Is your feature request related to a problem? Please describe.**
I would like to be able to store an alt text for an uploaded image in an easy, user-friendly way.

**Describe the solution you'd like**
Here's a mockup of what the feature could look like:


**Do you have a workaround?**
I could store a URL or file name and a corresponding alt text for each image in a file or a database.

**Comparable features in other tools?**
When uploading an image to social media sites, there is a way to attach an alt text to uploaded images, examples: [Twitter](https://help.twitter.com/en/using-twitter/how-to-use-alt-gif#:~:text=%22ALT%22%20is%20the%20abbreviation%20for,the%20image%20description%20will%20appear.), [LinkedIn](https://www.linkedin.com/help/linkedin/answer/a519856/adding-alternative-text-to-images-for-accessibility?lang=en).